Nokia has hit data rates of up to 4.7Gbps in a trial, by aggregating eight 100 MHz channels in millimeter wave bands with 40 MHz of LTE spectrum.
The key to very high speeds clearly lies in spectrum where applications can use at least 100 MHz of unencumbered airwaves, which means the bands above 20 GHz in most cases. However, these have challenges when it comes to range and penetration, and even 100 MHz channels are inadequate for some of the high capacity services envisaged for 5G.
In the decade before we reach the even loftier heights of ‘6G’ and ‘terahertz spectrum’ (see separate item), the main solution will lie in aggregating ever larger numbers of channels, from ever-more disparate parts of the spectrum, to maximize capacity while supporting coverage and fast hand-off too.
The Nokia test was carried out in Dallas, Texas on the network of an unnamed operator. According to the Finnish firm, it was conducted with ultra-low latency enterprise and mission-critical services in mind.
The test combined eight channels of 100 MHz each, in the 28 GHz and 39 GHz bands (the main mmWave bands in use in the USA). This was further aggregated with the 40 MHz of LTE spectrum using standard EN-DC (E-UTRAN New Radio – Dual Connectivity) capabilities. EN-DC supports the simultaneous connection of devices to 4G and 5G base stations, and so is foundational to 5G Non-Standalone networks, in which LTE and 5G networks both use the 4G core.
Its usefulness extends beyond that, however, because using both air interfaces at the same time, greatly increases the transmission speed compared to a single connection. And in this trial, the impact was heightened by the type and amount of spectrum being used for the 5G portion.
Nokia ran the trials using its AirScale base stations in both virtualized and physical baseband configurations, and said large-scale carrier aggregation in millimeter wave bands could pave the way for future terahertz communications.
Trials like this will be important to restore the perception of Nokia as a very advanced radio engineering firm, and dilute the memory of recent mis-steps in its early 5G products, which affected some of its US customers for a while. Tommi Uitto, president of mobile networks at Nokia, saids: “We already supply our mmWave radios to all of the major US carriers and we look forward to continuing to work closely with them moving forward.”